BACKGROUND: Hypertension is the major risk factor for stroke associated with small-artery disease and large-artery disease, but the factors behind the development of a particular stroke subtype in individual patients are not known. METHODS: We determined risk factors potentially predictive of stroke subtype in 822 of 2760 patients consecutively admitted to a primary care stroke center with (1) first-ever stroke, (2) hypertension (blood pressure &gt;160/90 mm Hg at least twice before the stroke), and (3) no cardioembolic source. We used logistic regression analysis to delineate factors associated with ischemic (brain infarct) vs hemorrhagic (primary hemorrhage) stroke and with large- vs small-artery disease. A scoring system was elaborated on the basis of the estimated regression coefficients. Observed proportions and calculated risks were determined. RESULTS: Age greater than 67 years, cigarette smoking, hypercholesterolemia, and a family history of stroke or ischemic heart disease were independent predictors of ischemic vs hemorrhagic stroke. In women, diabetes mellitus was an additional risk factor for ischemic vs hemorrhagic stroke. Only one of 144 patients with primary hemorrhage had an ipsilateral carotid stenosis. In men with brain infarct, cigarette smoking, cardiac ischemia, and a family history of stroke or ischemic heart disease were significantly and independently associated with large- vs small-artery disease. In women with brain infarct, smoking was the only predictive factor for large- vs small-artery disease. CONCLUSION: In patients with stroke and hypertension, associated risk factors influence the subtype of stroke (hemorrhage vs brain ischemia, large- vs small-artery disease).